Apparatus for and method of twisting and plying strands



June 18, 1968 A. w. VIBBER 3,388,542

APPARATUS FOR AND METHOD OF TWISTING AND FLYING STRANDS Filed Aug. 29, 1967 2 Sheets-Sheet 1 T1 l- 42 //Z 54A 249 'HHl /fl 0 i7 55 lo i4 -1 INVENTOR W AJ- 1415b June 18, 1968 A. w. VIBBER 3,388,542

APPARATUS FOR AND METHOD OF 'IWISTING AND FLYING STRANDS Filed Aug. 29, 1967 2 Sheets-Sheet E INVENTOR W ,(jwz z United States Patent 3,388,542 APPARATUS FOR AND METHOD OF TWiSTiNG AND PLYING STRANDS Alfred W. Vibber, 630 th Ave., New York, 10020 Filed Aug. 29, 1967, Ser. No. 664,135 17 Claims. (Cl. 57-585) ABSCT OF THE DISCLOSURE Apparatus for and method of combining two singles strands to form a wrapped strand product by the strand wrapping or skip twisting process. In the illustrated embodiment, the apparatus forms cords by plying together equal lengths of two singles strands. In such apparatus, one singles strand is ballooned about a source of supply of another singles strand, such two strands being combined under substantially equal tensions at a plying point beyond the balloon. The apparatus includes a balloon apex guide adjusted by variations in the relative tensions of the two singles strands approaching the plying point; the guide, which is adjusted in accordance with the difference in the tensions in the two singles strands, acts to maintain the substantial equality of such two tensions. The cord is pulled away from the plying point under tension, and preferably at substantially constant speed.

BACKGROUND OF THE INVENTION 1. Field of the invention The invention relates to an apparatus for and a method of combining or plying together two strands without adding to the twist of either. Such apparatus is of the so-called skip twisting type wherein a loop of one strand is rotated about a source of supply of another strand, the two strands being fed under tension to a wrapping or plying point and being taken up under tension and preferably at substantially constant speed from the wrapping or plying point.

2. Description of the prior art In my prior Patents Nos. 3,286,450 and 3,290,873 there are shown and claimed balloon tension control devices which are governed by the tension in one of the strands of the strand system associated with the spindle in a run of such strand disposed exteriorly of but in tension transmitting relation with the balloon. In such spindle the inner singles strand is fed to the plying point under constant tension, and the plied strand is withdrawn from the plying point at substantially constant speed, as in my Patent No. 3,153,893.

SUMMARY OF THE INVENTION In the illustrated embodiment of apparatus in accordance with the present invention, the outer singles strand is fed from its source of supply and to the plying point under tension by a capstan driven at constant speed, the inner singles strand is fed to the plying point under substantially constant tension, and the plied strand or cord formed by the spindle is pulled away from the plying point under tension at substantially constant speed, as in my Patent No. 3,153,893. With such apparatus it is possible to form cord which is very accurate in the number of twists per inch. In order to maintain the strand system, including the balloon, associated with the spindle under stable control, and to assure that the cord will contain equal lengths of two singles strands within very close limits, the present invention provides a novel control mechansim and method which maintain substantially constant at all times the ratio between the tensions in the runs of the two singles strands approaching the plying point. In the embodiment of apparatus illustrated herein, such tensions are maintained substantially equal.

Such control device includes an adjustable apex guide for the balloon, the guide being under the joint control of a first tension responsive means engaged by the outer singles strand and a second tension responsive means which is engaged by the plied strand. The first tension responsive means is positioned to engage the outer singles strand in the portion thereof between the constant speed feeding means therefor and the apex guide. The second tenison responsive means is positioned to engage the plied strand in the run thereof between the plying point and the means for feeding the plied strand away from the plying point under tension at substantially constant speed. The engagement of the strands with the respective tension responsive means is such that the torques imposed upon such means by the respective strands oppose each other; the device is also so constructed that the torque imposed upon the first tension responsive means by the outer singles strand tends to decrease the height of the balloon and thus to decrease the tension thereof, Whereas the torque imposed upon the second tension responsive means by the plied strand tends to raise the apex guide, thus increasing the height of the balloon and increasing the tension thereof.

The disclosed control device and the method performed thereby in effect measure the tension in the outer singles strand dierctly, measure the tension in the inner singles strand indirectly, and adjust the apex guide into the position at which both such tensions bear the desired relaitonship to each other. Thus in the illustrative embodiment of apparatus, in which it is desired that such tensions shall be equal, and in which the first and second tension responsive means are in the form of rollers, the first roller has a radius (2R) which is twice that of the second roller (R). When the angles of lap of the outer singles strand and the plied strand are adjusted appropriately, the torque imposed upon the first tension responsive roller is (where T is the tension in the outer singles strand, and K is a constant for one condition of adjustment of the apparatus, K including as factors (1) the coefiicient of friction between the outer singles strand and the first tension responsive roller, and (2) the angle of lap of such strand about such roller), and the torque imposed upon the second roller by the plied strand is T R k (where T is the tension in the plied strand, and k is a constant for the plied strand having components similar to those of K, but

Upon tension variations in the system as by reason of changes in diameter of the balloon, the disclosed control device functions to adjust the apex guide for the balloon to the height at which the tension in the two singles strands are equal. Thus such control device, because of the accurate feeding of the first, outer singles strand and of the plied strand, and the substantially constant tension to which the second, inner singles strand is subjected by its retarding or tensioning device, produces a system which at all times is in stable control and which produces a symmetrical cord having a substantially constant number of twists per inch.

BRIEF DESCRIPTION OF THE'DRAWINGS FIG. 1 is a fragmentary view in side elevation of an illustrative embodiment of twisting and plying spindle in accordance with the present invention;

FIG. 2 is a view in side elevation on an enlarged scale of a balloon and strand tension controlling mechanism employed in the apparatus of FIG. 1, certain of the parts being shown in vertical section;

FIG. 3 is a fragmentary view in section of the control device employed in the apparatus of FIG. 1, the section being taken along the line 3-3 of FIG. 2;

FIG. 4 is a view in horizontal section through the control device of the apparatus, the section being taken along the line 4-4 of FIG. 2; and

FIG. 5 is a fragmentary somewhat schematic view in tilted plan of the combined capstan employed in the apparatus of FIG. 1 which serves to feed the outer singles strand toward the balloon at substantially constant speed and the plied cord away from the plying point at substantially constant speed.

DESCRIPTION OF THE PREFERRED EMBODI- MENT In the embodiment of the apparatus shown in FIG. 1 the spindle is generally designated by the reference character 10. Such spindle is supported on a frame 11 having a horizontal enclosure portion 12 within which is contained driving mechanism for the hollow main vertical shaft 14 of the spindle which is rotatably mounted in a bearing housing 15 secured to enclosed portion 12. Nonrotatably mointed on shaft 14 and held against rotation by cooperating magnets as shown is a fixed support 16 upon which a package support 17 is mounted. An inner strand package 19 on support 17 supplies an inner strand [2. Strand b is paid off package 19, travels upwardly and then across the top of the package as indicated in dash lines in FIG. 1, and then proceeds downwardly to pass through a pre-tensioner 20 of the spring pressed washer type. From pre-tensioner 20, the strand b passes to strand handling device 21 on support 17.

The strand handling device 21 of the present apparatus is an idle strand tensioning means which is preferably adjustable to vary its strand tensioning effect. The tension device 21 is generally similar to that shown in FIG. 5 of the patent to Klein, No. 2,671,305, changed as to its orientation and the manner of feeding the strand into and away from the tension device. It is to be understood that other known strand tensioning devices may, if desired, be substituted for the tensioning device 21 here shown and described.

The strand b, after passing over a guide pulley 22, travels to the right (FIG. I) initially to contact the righthand roller 23 at the bottom thereof, and then travels counterclockwise around the roller to contact the left-hand roller 24 adjacent the bottom thereof. The strand b then travels clockwise around roller 24 and between such roller and an adjustably tensioned leaf spring 25 which has a curved free end overlying and conforming to the curvature of roller 24. As set forth in the above Klein patent, the ends of the shafts mounting rollers 23 and 24 are supported in guideways (not here shown) which lie generally parallel to the direction of the runs of the strand approaching roller 23 and leaving roller 24, the tension in the strand and the force exerted on the roller 24 through strand b by the leaf spring 25 causing the strand to be nipped forcibly between the rollers. The leaf spring 25 is secured at its upper end to support 16; the spring is adjustably thrust toward roller 24 by a set screw (not shown) threaded into a bracket afiixed to support 16. Strand b leaves roll 24 to pass partially about fixed guides 26 from which it travels upwardly to a canted central guide roller 27 and thence centrally down into the bore of the main spindle shaft 14 of the apparatus.

The outer, ballooned strand a is fed to spindle 10, in a direction from right to left, as from a single end strand package (not shown). Strand a passes through a fixed guide 28 on the frame of the spindle, to a further fixed guide 29, and thence upwardly and to the right to a first,

singles feeding portion of a combined capstan device geni erally designated 30. The construction and manner of operation of capstan 30 are illustrated most clearly in FIG. 5. Projecting forwardly from housing 12 is a horizontal shaft 31 which is driven in synchronism with and by the spindle shaft 14 of the apparatus by means such as gears not shown. Secured to shaft 31 is a stepped roller having a larger, forward circular cylindrical portion 32. Mounted on a bearing on a fixed, undriven stub shaft 34 projecting forwardly from housing 12 at a point spaced from shaft 31 is an idle roller 35. The outer strand a rises from guide 29 to pass clockwise over driven roller 32, passes over idle roller 35, and then repeatedly passes around such rollers in spaced runs, finally leaving roller 32 to pass to the right under fixed roller guide 36, up partially about a fixed roller guide 37, thence to a roller guide 39 on a cross arm 40 on standard 41, and finally to an upper tension responsive roller 43 of an apex guide and balloon and tension control device 42, to be described.

The described portion of the composite capstan 30 is provided with an idle presser roller 64 mounted on a lever 65 which is spring pressed to nip the runs of strand a between it and roller 32. The strand a is thus forwarded at substantially constant speed to the device 42 and thence into the balloon 74 which in this instance has an upper portion 75 and a lower portion 76.

After passing partially about the first or upper tension sensitive roller 43 of device 42, the strand a passes downwardly through the eye of an auxiliary fiyer 66, likewise to be described, and thence to the eye 45 adjacent the edge of a driven, balloon generating flyer disc 44 which is fixed to shaft 14 to rotate therewith. After passing through the eye 45, the strand travels generally radially inwardly to pass into an opening through the wall of shaft 14 to a cord forming die at the plying point P, where equal lengths of sitrands a and b are wrapped about each other to form cor c.

From the plying point P cord c passes down through. the lower end of the main spindle shaft 14 and thence downwardly to a fixedly mounted central guide roller 46 supported on the frame of the apparatus. From roller 46 cord 0 travels laterally to a further guide pulley 47, upwardly in a run 48 to an upper guide pulley 49, and laterally to the lower tension sensitive roller of the control device 42 as shown in FIG. 4. The pulleys 47 and 49 are mounted on fixed supporting structure, not shown. After passing partially about roller 50 and thence to an adjustable guide pulley 116 and a fixed guide pulley 117 (FIG. 4), the cord 0 travels in a run 52 to a fixed guide pulley 54 and thence in a vertical run 55 to a fixed guide pulley 56 mounted on fixed structure, not shown, the vertical runs 48 and 55 being angularly displaced. The cord 0 travels laterally from pulley 56 to a similar pulley 57 which is located below pulley 46. From pulley 57 the cord travels to the cord feeding portion of capstan 30 which takes it up at substantially constant speed and forwards it to a take-up package or bobbin 59.

The cord c rising from guide roller 57 first passes over the inner, smaller diametered circular cylindrical portion 60 of the stepped roller aflixed to driven shaft 31. The cord c then passes over an inner idle guide roller '61 rotatably mounted on shaft 34. Roller 61 is separate from and rotates independently of roller 35. After passing in multiple spaced runs about rollers 60 and 61, the cord 0 leaves the capstan by passing downwardly partially around roller 61 to a fixed guide 62 and thence to a movable guide 67 which is traversed by means not shown to lay the cord upon the bobbin 59 which is frictionally rim driven by a pair of rollers upon which it rests. One such driving roller, designated 69 in FIG. 1, is shown driven by means generally designated 70.

The portion of the capstan 30 which forwards cord 0 from the plying point P does so at substantially constant speed. Slippage of the cord on roller 60 is minimized by an idle presser roller 71 which is sepraate from and independent of presser roll 6- Roller 71 is mounted on a lever 72 which is spring pressed to urge the roller 67 forcibly against the portions of the cord lying between rollers 61) and 71.

The spindle 16 is provided with an auxiliary idle flyer 66 having an arm 77 with a guiding eye 78! therein through which the strand a of the balloon passes. Flyer 66 has an arm 89 extending oppositely from arm 77 for the purpose of counterbalancing the fiyer. The bearing 81 for the flyer 66 is mounted on the removable lid 82 of an enclosure 84 which is disposed about package 19 and is supported on the non-rotatable member 16 on shaft 14.

As shown, the eye 7 9 of auxiliary flyer 66 lies outwardly of the axis of shaft 14 of the spindle 10 at a radial distance which somewhat exceeds that of the eye 45 through the flyer disc 44. The upper portion 75 of the balloon 74 thus always lies in the first quadrant, that is, the strand :1 always enters the eye 7 9 of the auxiliary fiyer at an angle which is less than 90, measured inwardly toward the axis of the flyer, between the plane of rotation of the fiyer and a normal thereto at eye 79. It has been found that the use of the auxiliary fiyer 66 permits the use of a higher tension of strand a in the balloon and a higher speed of rotation of the spindle shaft 14 than would be permissible without it, and that the auxiliary flyer 66 assures the maintenance of the balloon free from contact with any fixed structure such as the lid 82 or the enclosure 84 about package 19.

The upper portion '75 of balloon 74 is a single balloon which spins above the bulge, that is, the balloon 75 has no true maximum diameter at all, because such bulge is situated in the imaginary continuation of the short balloon 75 below the auxiliary flyer 66. In such short balloon 75 the yarn tension is high, and an increase in the diameter of the short balloon 75 results in a greater yarn tension. The length of strand in the lower balloon portion 76 serves primarily to drive the auxiliary flyer 66. In any event, the tension variations caused by variations in the length of strand in portion 76 of the balloon are additive to those of the short balloon 75.

In the apparatus shown, the plying ploint P never is, by itself, a compensator for variations in balloon diameter. The use of the auxiliary flyer thus requires for all conditions of operation of the apparatus, that is, with yarn of uniform or yarn of varying unit weight, a balloon compensator which responds to variations in balloon diameter. This follows from the fact that with an increase in the diameter of the balloon, the tension in the strand a increases, whether the weight per unit length of the strand remains constant or increases. Thus the plying point per so can not function to restore the balloon to the diameter at which the balloon has the desired tension equalling that imposed upon strand [2 as it approaches the plying point.

The plying point P, however, acting in conjunction with the balloon control device 42, maintains the balloon 75, 76 under stabel control. Thus upon an increase in the diameter of the balloon, regardless of the cause, the device 42 acts to decrease the height of the balloon portion 75, and thus to decrease the tension in strand a as it approaches the plying point P until the tension in the strand a equals that in strand Z2. Upon such decrease of tension in strand a, the plying point functions to cause strand a to be absorbed into the cord c at a greater rate, thereby decreasing the diameter of the balloon 75, 76 to a predetermined value. When the diameter of the balloon 75, 76 decreases unduly, the control device 42 acts to increase the height of the balloon portion 75 and thus to increase the tension in strand a, whereby the plying point P then functions to cause strand a to be absorbed into the cord 0 ti at a slower rate, thereby increasing the diameter of the balloon 75, 76 to a predetermined desired value.

The construction and manner of operation of the control device 42 will be more readily apparent upon consideration of FIGS. 2, 3, and 4. A nut is mounted in a vertical opening adjacent the outer end of arm 40 and is retained therein by a set screw 86, as shown. An elongated, externally threaded, hollow spindle 87 is threadedly mounted in nut 85, the bore 89 in such spindle receiving the strand a as it passes downwardly from the guiding pulley 167 into the upper end of the balloon 74. The spindle 87 has a vertically rounded annular portion 91 inwardly thereof at the bottom of bore 89, the most constricted zone of portion 91 forming an annular guide 92 for the apex of balloon 74.

Rising above the main body of nut 85 and integral therewith is a short sleeve 94-. The above described tension sensitive rollers 43 and 50 are integrally connected to form a composite pulley 96. The pulley 96 is mounted on ball bearings 95 for rotation on the sleeve 94. The balloon control device 42 includes means for drivingly connecting the composite pulley 96 to the spindle 87 for joint rotation while permitting vertical adjustment of the spindle as it turns with respect to nut 85.

For this purpose, the outer surface of spindle 87 is provided with a plurality (two shown) of axially extending grooves 99, which may be of square section, for example, such grooves being angularly spaced about the axis of the spindle. The hub 100 of pulley 96 is provided with radially inwardly projecting lands 101 complementary to and accurately but slidingly interfitting with the grooves $9 in spindle 87. Turning of the pulley 96 in reverse directions thus causes the spindle 87 and the balloon apex guide 2 carried thereby to rise and fall, respectively.

The strand (1 upon leaving pulley 39 passes into contact with the smoothly concave periphery 102 of pulley 43, travels partially around such pulley, and then leaves it in a horizontal run 164 extending to a canted idle guide pulley 105. From pulley 105 the strand a travels upwardly in the run 106 toward the axis of spindle 87 to travel partially about a further idle guide pulley 107 which has its guiding surface on its exit side lying on the axis of spindle 37. From pulley 107 the strand a travels downwardly in a vertical run 110 into the top of the bore 8h in the spindle 3'7. As shown, the guide pulleys 105 and 1 37 are mounted on a member 169 of a frame 108 which is supported by a nut 112 upon a further fixed overarm 111.. The angular position of the frame 103, and thus, the angle of lap of strand a about pulley 43, may be adjusted by turning frame 168 and then tightening nut 112.

The strand a tends to turn the pulley 43 and the spindle 87 drivingly connected thereto in the direction of travel of such strand. The hand of the threads in nut 85 and on spindle 87 is such that rotation of the ulley 43 and the spindle 87 in the direction of travel of the strand (1 causes a lowering of the spindle with a consequent decrease in height of the balloon 74.

The torque imposed upon the pulley 43 is opposed by that imposed upon the pulley 50 by the strand 0 passing thereabout. The manner of interaction of the strand 0 with the pulley 56 is more clearly apparent in FIG. 4. The cord 0 upon leaving the surface of pulley 50 passes partially about a guide pulley 116 to leave the latter pulley to travel to a fixed guide 117. The guide pulley 116 is adjustably mounted upon a plate-like end portion 114 of the overarm 46. As shown, an arcuate slot 115 is provided in portion .114, the guide pulley 116 being mounted to be adjusted and then secured in the angular position in the slot 115 which yields the desired angle of lap of the strand c about the pulley 50.

It will be seen that the strand a acts upon the tension sensitive roller 43 in one direction and that the plied strand 0 acts upon the tension sensitive roller 50 in the other, opposite direction. In the embodiment shown the tension sensitive roller 40 has a radius (2R) which is twice that (R) of roller 50. It will be understood, however, that the desired equality of torques in opposite directions imposed upon the composite roller 96 by the strands a and may be secured, with other relative radii of rollers 43 and 50, by suitable adjustment of the angle of lap of the strands about the respective rollers. The parts of the apparatus are so adjusted that under stable operating conditions, with the strand a of a known weight per unit length, with a balloon having a known desired tension, and with the retarding device 21 adjusted to impose the same known desired tension upon strand b, the spindle 87 carrying the apex guide 92 is at rest at a predetermined vertical position. Upon a variation of balloon tension the apex guide is vertically adjusted, as above described, to restore the equality of tension in the strands a and b approaching the plying point.

It will be seen from the above that the torques imposed upon the tension sensitive rollers 43 and 50 by the strands a and c, with the proper adjustment of the apparatus, are directly proportional to the tensions in such respective strands when the coeflicients of friction between the strands and rollers 43 and 50 remain constant. Thus when the torques imposed upon rollers 43 and 50 are equal and opposite, the tension T of strand a equals the tension T of strand b, because T the tension of the plied strand c, includes as components T and T Thus when the radius of roller of pulley 43 is 2R, and the radius of roller or pulley 50 is R, the torque imposed on roller 43 by strand a equals T -2R-K, where K is a constant for one condition of adjustment of the apparatus, K including as factors (1) the coefiicient of friction between strand a and roller 43, and (2) the angle of lap of strand a about roller 43. The torque imposed on roller 50 by plied strand 0 equals T -R-k, k including as factors (1) the coefiicient of friction between plied strand 0 and roller 50, and (2) the angle of lap of plied strand 2 about roller 50. By a suitable choice of material from which the strand engaging surfaces of rollers 43 and 50 are made, and a suitable choice of the angles of lap of strands a and 0 about the rollers 43 and 50, K can be made equal to k.

Under such conditions, when the tensions of strands a and b approaching the plying point P are equal, T a2R.=--T -R, the strands a and c slip past the surfaces of rollers 43 and 50, and the apex guide is at rest.

But

o u'i' b so that T -2R=T -R+T -R and It will thus be seen that the apparatus of the invention functions to give a direct measurement of the tension of strand (1 by the interaction of such strand with roller 43, to give an indirect measurement of the tension of strand b by virtue of the interaction of plied strand 0 with roller 50 and the relationship T =T +T and adjusts the apex guide to bring T back to equality With T should the balloon diameter and/ or tension vary appreciably.

Although the two tension responsive members 43 and 50 are shown as being drivingly connected to the apex guide adjusting means, they could, in alternative constructions, be employed to control the application of power in reverse directions from a separate source of power to the apex guide adjusting means in manners disclosed in applicants Patent No. 3,290,873. The composite tension responsive member 43, 50 of the present invention and the means for feeding the outer singles strand and the plied strand to and away from the parts 43 and 50, respectively, thereof could be substituted for the single tension responsive member and the strand feeding means associated therewith in each of the three embodiments of apparatus disclosed and claimed in Patent No. 3,290,873.

Although in the illustrative apparatus the wrapped strand product or plied strand is taken up on its individual take-up bobbin or package, with some modification a plurality of the illustrated spindles may feed their strand products to be taken up on a comon take-up beam. Thus instead of the take-up capstan 6-9, 61, 71 for the strand product illustrated herein there may be employed a take up capstan for each spindle which is similar to that shown in either Clarkson Patent No. 3,058,681 or Clarkson et al. Patent No. 3,108,427 but without the presser roll 48 of the former and the presser roll 26 of the latter. Both of such patents disclose oord take-up capstans which are, in effect, cat-head capstans in which the hand of the operator is replaced by a V-groove on a surface which travels at a higher surface speed than that of the rotating surface upon which multiple wraps of the cord are disposed, The cord upon leaving the V-groove travels to the common take-up beam upon which it is wrapped at substantially constant speed but under a tension which is markedly less than that existing in the cord in advance of the takeup capstan.

The V-groove functions as a trigger which is sensitive to variations in tension in the cord in the run thereof between the take-up capstan and the common take-up beam. Upon an increase in tension in such run of the cord, the take-up capstan functions to pull the cord from the plying point at a higher speed; upon a decrease in tension in such run of the cord, the take-up capstan functions to pull the cord from the plying point at a lower speed. The total variation in such speed of pulling of the cord is small, and so even with such modified apparatus the capstan or means for feeding the wrapped strand product is properly described as feeding such product at substantially constant speed. The disclosed adjustable apex device functions to maintain the desired ratio between the tension of the two strands approaching the wrapping or plying point despite such small variations in the speed of take-up of wrapped strand product or cord as may occur at the take-up capstan, whether such capstan is that illustrated herein or is the modified, cat-head capstan described immediately above.

It will be apparent that the apparatus and method of the invention may be employed to advantage in a number of dilferent skip twisting spindles other than that illustrated, which produces symmetrical two-ply cord. The apparatus and method may be employed, for example, in strand-covering apparatus such as that shown in Clarkson Patent No. 2,737,773, wherein a covering strand is wrapped around a central elastic strand. They may also be employed in spindles wherein the singles strands, although essentially inelastic, are fed to the wrapping or plying point at different predetermined speeds to produce an unsymmetrical wrapped strand product which incorporates predetenmined different lengths of the two singles strands. In both such last described embodiments of apparatus in accordance with the invention the rotatable tension responsive members are made of such relative diameters and with such coefficients of friction with respect to the respective strands which they engage that when they are at rest and in torque equilibrium the two strands approaching the wrapping or plying point will have the desired ratio of tensions relative to each other.

Although a limited number of embodiments of the invention have been illustrated in the accompanying drawings and described in the foregoing specification, it is to be especially understood that various changes, such as in the relative dimensions of the parts, materials used, and the like, as well as the suggested manner of use of the apparatus of the invention, may be made therein without departing from the spirit and scope of the invention, as will now be apparent to those skilled in the art.

I claim:

1. Apparatus for combining two singles strands to form a wrapped strand product by the strand wrapping process, comprising a source of supply of a first singles strand,

means for feeding a first singles strand forward from its source of supply to a strand wrapping point, a source of supply of a second singles strand, means for feeding the second singles strand forward from its source of supply, for forming a balloon in the thus fed second singles strand about the source of the first singles strand, and for feeding the second singles strand from the balloon to the wrapping point, means for feeding the plied strand under tension away from the wrapping point, and means for controlling the relative tensions of the two singles strands approaching the wrapping point, said last named means including an apex guide for the balloon poisitioned coaxially of the balloon adjacent the apex end thereof, adjustable means supporting the apex guide for movement axially of the balloon to vary the height of the balloon, and mechanism for controlling the last named means comprising a first rotatable tension responsive means disposed to be engaged by and turned by a run of the second strand which is in tension transmitting relation with but exteriorly of and spaced from the balloon, a second rotatable tension responsive means disposed to be engaged by and turned by a run of the wrapped strand product which is in tension transmitting relation with the wrapping point, and means responsive to the rotation of both the first and second tension responsive members to adjust the supporting means for the apex guide.

2. Apparatus as claimed in claim 1, comprising means drivingly connecting the first and second tension responsive members for joint rotation in accordance with the resultant of the torques imposed upon them by the respective strands engaging them.

3. Apparatus as claimed in claim 2, wherein the first and second tension responsive members are drivingly connected to each other and to the adjustable means supporting the apex guide.

4. Apparatus as claimed in claim 2, wherein the first tension responsive means is disposed between the balloon and the means for feeding the second strand toward the balloon.

5. Apparatus as claimed in claim 4, wherein the feeding means for the second strand feeds such strand at constant speed, and the run of said second strand extending from said feeding means to the balloon is tight and in tension transmitting relationship with the balloon.

6. Apparatus as claimed in claim 5, wherein the means for feeding the first singles strand from its source of supply and toward the wrapping point feeds such strand under constant tension.

7. Apparatus as claimed in claim 6, wherein the means for pulling the wrapped strand product from the wrapping point feeds the wrapped strand product at substantially constant speed.

8. Apparatus as claimed in claim 4, wherein the means for adjusting the means for supporting the apex guide is such, and the first and second tension responsive means so control said adjusting means that travel of the surface of the first tension responsive means in the direction of travel of the second strand in engagement therewith urges the said apex guide support in the axial direction to decrease the height of the balloon, and that travel of the surface of the second tension responsive means in the direction of travel of the wrapped strand product in engagement therewith urges the said apex guide support in the axial direction to increase the height of the balloon.

9. Apparatus as claimed in claim 8, comprising an auxiliary flyer engaging the balloon of the second strand adjacent the apex guide so that the short balloon formed between the apex guide and the auxiliary flyer always rotates in the first quadrant, and wherein the first and second singles strands are similar and the wrapped strand product is a plied strand containing substantially equal lengths of the first and second singles strands, and wherein the strand engaging surfaces of the first and second tension responsive means have effective radii and have coefficients of friction with the strands which they engage such that when the torques imposed on the two tension responsive means by the respective strands are equal and the apex guide is at rest the tensions in the two singles strands approaching the wrapping point are equal.

10. Apparatus as claimed in claim 1, wherein the first and second tension responsive means are in the form of pulleys, said pulleys being coaxial and connected for joint rotation, and the torques imposed upon the pulleys by the respective strands engaging them oppose each other.

11. Apparatus as claimed in claim 10, wherein the adjusting means for the apex guide supporting means comprises two threadedly engaged threaded means of which one is said rotatable member, one of said threaded means being connected to the apex guide so as to travel with the apex guide as it is adjusted axially of the balloon, the other of the threaded means being fixed from travel with said apex guide.

12. Apparatus as claimed in claim 11, wherein the means mounting the apex guide mounts it for rotation about its axis, and comprising means drivingly connecting the apex guide to the pulleys so that the guide and pulleys rotate in synchronism.

13. In a method of combining two strands to form a wrapped strand product which includes feeding a first strand from a source of supply thereof, rotating a zone of the first strand in the form of a loop about a let-off package for a second strand, withdrawing the first strand from the loop and bringing it into engagement with the second strand at a strand wrapping point beyond the loop, feeding the first strand at substantially constant speed into the loop, feeding the second strand to the wrapping point under substantially constant tension, and feeding the wrapped strand product away from the wrapping point at substantially constant speed, the improvement which comprises detecting changes in the tension of the strand in the loop by a first tension responsive means, detecting changes in the tension of the wrapped strand product by a second tension responsive means, determining the algebraic sum of said two tensions by combining the responses of said first and second tension responsive means, and varying the tension of the strand in the loop in accordance with changes in said algebraic sum to restore the tension of the first strand in the run thereof immediately in advance of and extending to the wrapping point to substantially that of the second strand in the run thereof immediately in advance of and extending to the wrapping point.

14. A method as claimed in claim 13, wherein the tension of the strand in the loop is varied by changing the height of the loop in accordance with changes in the algebraic sum of said tensions.

15. A method as claimed in claim 13, comprising diverting the run of the first strand between the feeding means therefor and the apex guide by a first rotatable tension responsive member, diverting the run of the plied strand between the feeding means therefor and the wrapping point by a second rotatable tension responsive member, combining the torques thus generated upon the two tension responsive members to obtain the algebraic sum of such torques, and varying the tension of the strand in the loop in accordance with changes in said algebraic sum of the said torques.

16. A method as claimed in claim 15, wherein the two tension responsive members are drivingly connected, and the torques generated upon the two tension responsive members oppose each other.

17. A method as claimed in claim 16, wherein the first and second singles strands are similar, the wrapped strand product is a plied strand containing substantially equal lengths of the first and second singles strands, and the strand engaging surfaces of the first and second tension responsive means have effective radii and have coefiicients of friction with the strands which they engage such that the torques imposed on the two tension responsive means by the respective strands are equal and the apex guide is at rest when the tensions in the runs of the first and second strands immediately in advance of and extending to the Wrapping point are equal.

Vibber 57-583 Klein 57-58.3 Vibber 57-58.3 Vibber 57-583 Vibber 5758.3

FRANK J. COHEN, Prim ry Examiner.

D, E. WATKINS, Assistant Examiner. 

